A surface acoustic wave device and a preparation method thereof

Abstract

The invention discloses a surface acoustic wave device, which divides the interdigital transducer bus bars into a gap region, an edge region and an intermediate region, and the directions from any busbar to the two bus bars are the gap region, the edge region and the intermediate region in turn. By arranging the hill layer covered by the electrode between the piezoelectric substrate and the electrode, the acoustic wave velocity in the gap region is larger than the acoustic wave velocity in the intermediate region, and the acoustic wave velocity in the intermediate region is larger than the acoustic wave velocity in the edge region. The waveform propagated between the interdigital transducers can be filtered into the piston waveform by the above arrangement, thereby filtering the remainingwaveforms of the non-piston waveform, thereby effectively reducing the parasitic mode of the surface acoustic wave device, and enabling the surface acoustic wave device to have a higher quality factor. The invention also provides a preparation method of a surface acoustic wave device, and the surface acoustic wave device prepared by the method also has the beneficial effects.

Description

technical field [0001] The invention relates to the field of acoustic wave devices, in particular to a surface acoustic wave device and a preparation method thereof. Background technique [0002] With the continuous advancement of science and technology in recent years, surface acoustic wave devices have been greatly developed. The so-called surface acoustic wave is an elastic wave that is generated and propagated on the surface of a piezoelectric solid material, and whose amplitude decreases rapidly as the depth of the solid material increases. Compared with bulk acoustic waves propagating along the interior of solid media, surface acoustic waves have two remarkable features: one is high energy density, of which about 90% of the energy is concentrated in a thin surface layer with a thickness equal to one wavelength; the other is slow propagation speed , which is about 45% of the longitudinal wave velocity and 90% of the shear wave velocity. [0003] Based on the above-men...

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Problems solved by technology

[0005] However, in the prior art, the number of spurious modes cannot be effectively reduced by the apodization method, so the effect on improving the quality factor of SAW devices is limited

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